Generally, cutting tools are used for machining various kinds of workpieces. Such a cutting tool is mounted to a machine tool and conducts a cutting operation to form a workpiece into a desired shape.
Typically, a cutting tool includes a cutting insert having a cutting blade, which substantially conducts a cutting operation, and a cutter body which supports the cutting insert.
There are two methods to cut a metal workpiece using a cutting tool. In a first method, a fixed cutting tool cuts a workpiece, which rotates. In a second method, a tool, which has a cutting blade and rotates, cuts a fixed workpiece.
Milling conforms to the second of the above-mentioned cutting methods. Plane machining, side machining, groove machining, hole machining, etc. can be carried out by a milling cutter.
Many efforts have been conducted to reduce resistance during the machining process of a milling cutter, to extend the lifetime of a tool, and to enhance the machining quality.
However, in conventional cutting inserts, even if a cutting blade part is provided on each of opposite ends of a cutting insert, because the cutting insert is mounted to a cutter body in only one direction, only part of the corner blades or main blades of the cutting blade parts is used for cutting workpieces. Therefore, there is a problem in that the lifetime of the cutting insert is reduced.